Does anything in this conversation sound applicable to your troubles: http://rswarrior.com/forums/t/22937.aspx If yes, and since you do NOT have a Power Commander, many suspect the CPS as others have stated above. See also http://rswarrior.com/forums/p/18636/278528.aspx#278528 first paragraph - if read with knowledge that you don't have a PC3 then it leaves a broken CPS as the likely problem. However the TPS may be the only sensor that is rpm-sensitive, or more accurately when you twist the grip so far it'll cause the motor to run at 3,000 rpm so if the TPS is stuck or faulty it would possibly cause this symptom and if it does cause this symptom it would be at a particular rpm. But the TPS as the solution to this problem isn't proven since some have had their CPS and TPS replaced without solving this issue. At least one member replaced the TPS and cured it. So the mystery lingers.
I've just scanned the entire owner manual, service manual, service manual addendum, and parts manual. Excluding the ECU and Tach of course, the only electrical parts that act on the basis of rpm are the speed sensor and throttle position sensor. The speed sensor only cares if forward motion is above or below a very slow speed (generally for the turn signal auto-cancel function). The TPS isn't really reading rpm but the amount of pull on the throttle cable by detecting the throttle valve angle, then the TPS translates this info into accurate assumptions about the throttle position based on voltage. (clarified 6 24 2008)
Please let us know if that corrects the trouble. There's a handful of members with this trouble and many of us are very interested.
love_snot:
At 3000rpm, and only 3000rpm in 5th gear, my bike will sputter & backfire...and only if I'm gently twisting the throttle. Runs great in every other gear and at every other rpm in 5th gear?? So, if I'm cruising at about 75mph, for me that's about 2800rpm it's great. If I gently try to increase to, or stay at, 3000rpm the bike will sputter, backfire and surge...terrible feeling. The second I hit 3100rpm it's great again? Like I said, this only happens in 5th gear. I have the ais blockoff, Churchkey's V-BAK and Bub's Jug Huggers. The plugs are perfect, no pcIII, I just used the ecu to adjust. I've read through tons of discussions on these fourms but I don't see anyone that has the exact same problem. I don't think it's the tps or the throttle bodies because it's only that rpm and only in 5th gear...or could it be? Would installing a pcIII and getting a custom map cure this? I don't have the money to do that or I would've already tried it.
Any and all help/suggestions is greatly appreciated as I'm getting quite annoyed with this. Thanks in advance.